openBmap-locator (was Re: Ericsson releases "free" cell-id lookup API)

Baruch Even baruch at
Fri Oct 23 17:58:01 CEST 2009

Alex (Maxious) Sadleir wrote:
> 2009/10/23 Baruch Even <baruch at>:
>> Alex (Maxious) Sadleir wrote:
>>> 2009/10/23 Onen < at>:
>>>> Baruch Even wrote:
>>>>> Alex (Maxious) Sadleir wrote:
>>>> As Baruch said, you must be online, and I add you must send your GSM
>>>> data (and as such your position) to a third party.
>>>> Local service on the phone as openBmap-locator from Baruch is the right
>>>> way to go for performance, easiness, and privacy.
>>> I look forward to this :)
>> Search for openbmap-locator, it already exists. Though it's still
>> somewhat limited.
> I have tried it successfully but wasn't sure if you wanted to draw
> attention to it yet.

I wasn't planning to but since there was a mention already and the code 
is out there I saw no reason to hide it.

> The accuracy even on the primitive algorithm was ok (still within
> 1-2km of actual position).

It depends on the difference between where the cells were measured from 
and where you are. I have a testcase where I measured the data on a 
train and then look for my location on that train, in that case it's 
near perfect :-) but normally I expect this algorithm to be not so 
accurate. But it works to give a rough location.

> I've weighted average cell positions by max radius and signal strength
> before and they "seemed" more accurate - but that technique is quite
> naive anyway (sometimes a far off cell would skew the results).
> Certainly, if anybody has an idea for a cell location algorithm, this
> is a good app to test it with.

The work needs to progress in two related directions, estimating cell 
positions and estimation mobile position based on that.

> I also tend to get "(0, 0, 0.0, 0.0, 0.0)" sometimes when I check many
> times in a row which probably isn't the fault of openbmap-locator
> because looking at the FSO result for neighbouring cells at those
> times returns results such as:
> ie. Results where the cellID = 0000 (sometimes for serving cell even
> when the FR display shows full signal strength). Perhaps
> openBmap-locator needs to collect a couple of results in a row if it
> doesn't already.

Known issue but I was hurrying to get something out so I ignored it.

> Is there already a way to trick ogpsd into using the openbmap-locator
> dbus interface? or is that still future research/improvement?

Not that I know of. I managed to use a configuration for fso-gpsd to use 
  openbmap-locator but there is nothing that can merge the two signals 
and use the better one that is available.


More information about the community mailing list